1. Field of the Invention
The present invention relates to a process for the production of acetals from the reaction of a linear alkyl alcohol with an aldehyde. More particularly the invention relates to a process wherein the reaction is carried out simultaneously with the separation of the reaction products (water and methylal) from the reactants.
2. Related Art
It is known that acetals may be synthesized from alcohols and aldehydes in the presence of an acidic catalyst through a condensation reaction as illustrated by the following equations; ##STR1##
The IUPAC names for each of the reaction products is as follows:
(1) methanol+formaldehyde yields dimethyl acetal formaldehyde; common name methylal or dimethoxy methane PA1 (2) ethanol+formaldehyde yields diethyl acetal formaldehyde; common name ethylal or diethoxy ethane PA1 (3) methanol+acetaldehyde yields dimethyl acetal acetaldehyde; common name 1,1 dimethoxy ethane PA1 (4) ethanol+acetaldehyde yields diethyl acetal acetaldehyde; common name 1,1 diethoxy ethane or acetal.
While "acetal" is one of the common names of diethyl acetal acetaldehyde, the term acetal as used herein means the reaction product of an alcohol with an aldehyde.
Acetals are considerably more stable to alkalies than to acids. They are considered so much more stable than free aldehydes to the action of basic reagents and oxidizing agents that aldehydic compounds are often converted into the acetals to protect the aldehydic function from damage during the course of synthesis operations involving other parts of the molecule.
Methylal is useful in the production of high concentration formaldehyde as disclosed in U.S. Pat. No. 4,967,014. Therein a two step process for the production of highly concentrated formaldehyde is disclosed wherein the first step is to react methanol with lower concentrations of formaldehyde to form methylal and the subsequent oxidation of the methylal to formaldehyde. Methylal is also useful for extracting certain sulfonated organic compounds from the alcohols used to prepare such compounds as disclosed in U.S. Pat. No. 4,096,175.
U.S. Pat. No. 4,385,965 discloses a process for the recovery of pure methylal from methanol-methylal mixtures. U.S. Pat. No. 5,223,102 discloses a process for the electrooxidation of methanol to formaldehyde and methylal.